1. Field of the Invention
The present invention relates to polymers, and particularly to a method to produce ultra-high molecular weight polyethylene (UHMWPE) using a tungsten-doped titania (TiO2/W) nanofiller.
2. Description of the Related Art
Ultra-high molecular weight polyethylene (UHMWPE) is an exceptional polymer with unique mechanical and physical properties such as chemical resistance, impact resistance, abrasion resistance, lubricity and thermal stability. These properties are directly related to the molecular and super molecular structure of the polyethylene polymer. Ultra-high molecular weight polyethylene is obtained by polymerizing ethylene at low pressure using Zeigler-Natta catalyst supported by fixing TiCl4 or VOCl3 onto amorphous SiO2. Recently methyl aluminum dichloride (MADC) was found to be a potential cocatalyst in the polymerization/oligomerization process.
It is common in the plastics industry to blend various additives with a matrix polymer for the purpose of improving one or more polymer physical properties. Such compositions that contain nanofillers dispersed in a polymer matrix are referred to as nanocomposites. Polyolefin nanocomposites are of great interest in industry because they possess exceptional mechanical properties, flammability, gas barrier properties and thermal stability depending on their shape, loading, particles size, dispersion of the fillers and bonding. Polymer composites have been made by (a) solution mixing, (b) melt compounding and (3) in situ polymerization. Among these methods, in-situ polymerization is considered to be more promising since it leads to a homogeneous dispersion of filler in the polymer matrix.
In recent years, highly effective nanoparticle fillers have been developed and used as additives in polymer matrices. For example, various inorganic nanoparticles have been used as nanofillers such as titanium dioxide (TiO2), silicon dioxide (SiO2), aluminum trioxide (Al2O3) and zinc dioxide (ZrO2) to improve polymer properties. Polymer-based TiO2 composites have been extensively studied in the literature to improve mechanical and thermal properties of the polymer. Although TiO2-filled polymers are known, the properties of such composite materials are fixed.
It would be desirable to provide a method for producing ultra-high molecular weight polyethylene (UHMWPE) with tungsten doped titania nanofiller material (TiO2/W) that permits control over and variation of the overall polymeric properties, such as molecular weight and the associated thermal properties.
Thus, a method to produce ultra-high molecular weight polyethylene solving the aforementioned problems is desired.